It is generally required that multiple silicon-on-insulator optical ring resonators coupled to the same waveguide and/or optical bus be spaced in resonant frequency at a specific step-size (e.g. 50 GHz, 200 GHz, etc.). The variance in fabrication of multiple silicon-on-insulator optical ring resonators (e.g. etch-depth, width etc.) is such that it is usually not possible to space the resonances with sufficient accuracy or precision. Thus, thermal tuning of each individual optical ring resonator is used such that the specific spacing is achieved during operation. This adds complexity to the control circuit performing the thermal tuning, and requires additional power dissipation for the device. Physical post-fabrication “trimming” of the resonant condition of optical ring resonators can be performed, for example, by the removal/addition of material from the optical ring resonators. This can be achieved using thin film deposition, etching, or laser ablation. In all cases, it is required that a local structure of the optical ring resonator be physically altered with precision on the order of hundreds of nanometers, which can be challenging, time consuming and not compatible with a thick cladding layer generally used with optical ring resonators.